High Quality Chainsaw Bars Husqvarna Toys Hockfire Saws

Mantis tiller issue

razrook

New OPE Member
Local time
9:02 PM
User ID
35712
Joined
Mar 11, 2026
Messages
3
Reaction score
3
Location
Serbia
Hi all, thanks for having me - I'm new here and have a very little experience, hoping to get some help and guidance. Thanks in advance.

I got this Mantis tiller used, and it ran fine, had a little gas in there too. I used it and had to add some gas mixture (1:50, made it myself with Stihl 2 stroke oil). Starting it, I noticed that the priming bulb is now cracked and it leaks just a bit.

Couldn't start it at first, but managed to start it with the choke open (running position). Idle is ok, and the adjustment screw reacts fine, but adding throttle, the engine varies in power by itself, with even distances between attacks - in the video I'm only holding full throttle, it's doing the revs by itself.

My amateur guess is that it's the obvious bulb issue, causing it to pull air. Another thing is that I may have overfilled the tank a bit, covering the vent hose, but I took out the excess without resolveing the problem. Maybe I have added a bit more oil, but it's like a teaspoon tops.

Otherwise, everything looks clean and almost like new - the air filter and fuel filter are clean.

I'd appreciate any input, thanks again.
Cheers!

 

singinwoodwackr

Pinnacle OPE Member
Yearly GoldMember
Local time
2:02 PM
User ID
34279
Joined
Sep 14, 2025
Messages
877
Reaction score
2,576
Location
moon
Country flag
Hi all, thanks for having me - I'm new here and have a very little experience, hoping to get some help and guidance. Thanks in advance.

I got this Mantis tiller used, and it ran fine, had a little gas in there too. I used it and had to add some gas mixture (1:50, made it myself with Stihl 2 stroke oil). Starting it, I noticed that the priming bulb is now cracked and it leaks just a bit.

Couldn't start it at first, but managed to start it with the choke open (running position). Idle is ok, and the adjustment screw reacts fine, but adding throttle, the engine varies in power by itself, with even distances between attacks - in the video I'm only holding full throttle, it's doing the revs by itself.

My amateur guess is that it's the obvious bulb issue, causing it to pull air. Another thing is that I may have overfilled the tank a bit, covering the vent hose, but I took out the excess without resolveing the problem. Maybe I have added a bit more oil, but it's like a teaspoon tops.

Otherwise, everything looks clean and almost like new - the air filter and fuel filter are clean.

I'd appreciate any input, thanks again.
Cheers!

a great little tiller...I've had an older one but got a newer model last year.
It won't work with a cracked primer bulb. The easiest thing to do on these is just replace the carb and fuel lines/filter. I did that with my older one and all issues disappeared.
 

EFSM

Pinnacle OPE Member
Local time
3:02 PM
User ID
29079
Joined
Apr 30, 2024
Messages
1,385
Reaction score
3,345
Location
Extreme southern IL
Country flag
If the check valves in the primer base are working properly, a new primer bulb won’t make a difference. If they are leaking, then it might help. I would guess it’s also got a stiff metering diaphragm, which would be easy enough for you to change while replacing the bulb (it’s right underneath the black primer base). Of course you won’t need this many, but this is what you need.
It is an Echo engine, so any Echo dealer should have parts.
Filling the tank full isn’t an issue.
IMG_1039.jpeg
 

singinwoodwackr

Pinnacle OPE Member
Yearly GoldMember
Local time
2:02 PM
User ID
34279
Joined
Sep 14, 2025
Messages
877
Reaction score
2,576
Location
moon
Country flag
If the check valves in the primer base are working properly, a new primer bulb won’t make a difference. If they are leaking, then it might help. I would guess it’s also got a stiff metering diaphragm, which would be easy enough for you to change while replacing the bulb (it’s right underneath the black primer base). Of course you won’t need this many, but this is what you need.
It is an Echo engine, so any Echo dealer should have parts.
Filling the tank full isn’t an issue.
View attachment 484896
I rebuilt my carb…fixed some issues but was still a pain to use so just replaced the whole thing. The kit came with carb, lines, filters, etc.
 

razrook

New OPE Member
Local time
9:02 PM
User ID
35712
Joined
Mar 11, 2026
Messages
3
Reaction score
3
Location
Serbia
a great little tiller...I've had an older one but got a newer model last year.
It won't work with a cracked primer bulb. The easiest thing to do on these is just replace the carb and fuel lines/filter. I did that with my older one and all issues disappeared.
Thanks! Yes, it's great and simple enough to get my teeth in the whole thing with engine tools. People out there love them, and I was sorry to get this sort of issues so soon, as it felt like I broke it somehow. Will start with replacing the bulb. Cheers!
 

razrook

New OPE Member
Local time
9:02 PM
User ID
35712
Joined
Mar 11, 2026
Messages
3
Reaction score
3
Location
Serbia
If the check valves in the primer base are working properly, a new primer bulb won’t make a difference. If they are leaking, then it might help. I would guess it’s also got a stiff metering diaphragm, which would be easy enough for you to change while replacing the bulb (it’s right underneath the black primer base). Of course you won’t need this many, but this is what you need.
It is an Echo engine, so any Echo dealer should have parts.
Filling the tank full isn’t an issue.
View attachment 484896
Thank you for the input - the weird thing is that it was working just fine before the fuel refill. Think the bulb wasn't even cracked, but I squeezed it a bit harder priming it, and it must've cracked then, because there was no leaking before, and now it drips as it runs. So, I don't know why the diaphragm would suddenly go stiff, but it's good that it's easily replaceable, only for the price of the pack I could get a complete carb replacement with lines...
 

LS50713

Well-Known OPE Member
Local time
1:02 PM
User ID
14303
Joined
Oct 25, 2020
Messages
13
Reaction score
20
Location
Sweet Home Oregon
Country flag
I fixed my Mantis Tiller by buying a new Honda 4 stroke tiller. Problem solved, no more rebuilding the poor excuse for a carb every year. Yes I use the best of fuels and mix oil. Always stored with a full tank and bit of Stabill, gonna be my kids problem from here out. ;)
 

Junk Meister

Pinnacle OPE Member
GoldMember
Local time
3:02 PM
User ID
1674
Joined
Aug 10, 2016
Messages
1,513
Reaction score
4,671
Location
Nebraska
Country flag
If the primer bulb is weeping/leaking I would reread post #1 and #2. the check valve may have issues that may clear with fresh fuel running through it. Don't be surprised if the fuel lines and filter need replaced as well. Strongly suggest not running any fuel containing Ethanol in it..
Welcome to O P E....
 

Brad Button

Super OPE Member
Local time
1:02 PM
User ID
4979
Joined
Jan 6, 2018
Messages
122
Reaction score
242
Location
Angels Camp,Ca.
Country flag
New carburetors are cheap. Just make sure you do not get an aftermarket. It should have a Zama carb on it. And like someone else mentioned, replace the fuel lines and the tank grommet. You will have better luck using the pre-mixed in a can, as those little tillers usually don't get used very often. Stay away from the Tru-Fuel brand if you go that route.
 
Top